The only real difference between what the OE's and cornering enthusiasts call (variously) a stabilizer bar, "sta-bar", antiroll bar, or more informally as a "swaybar", and what the drag strip enthusiast knows as an antiroll bar is the stiffness of the bar in question.
How the bar is connected to the axle and the chassis or whether it is simply bolted to the LCAs is a difference in detail but not function. That said, the length of the LCAs ends up making the LCA-connected bars on these cars (and the B-bodies and the Fox/SN95 Mustangs as well) softer than if you hooked the very same bar to the axle and chassis instead.
The reasons for both the cornering and straightline groups to use a rear bar of some sort is actually pretty much the same - to attract some of the resistance to chassis/body roll back to the rear axle. It's only the amount of load transfer you want to drag back there that differs, hence the huge difference in bar stiffness.
Normally, the cornering enthusiast wants only a little more rear roll stiffness in order to help balance the front stiffness, so a relatively small bar is all that is required.
The dragstrip guy wants lots more of the lateral load transfer to go back, as rear roll stiffness helps plant the RR back down by using the engine torque reaction carried back through the chassis. Hence the huge bar . . .
Incidentally, disconnecting the front bar also shifts the distribution of roll resistance rearward, at least up to the point where you've pulled the LF tire up.
Less roll also means less rear axle roll steer (another rear suspension property defined by the angles of the links/arms), which equals less tendency for the car to go hunting for walls and other things outside the lane. LCA relocation brackets can actually help fix this problem as well. This axle roll steer itself is sort of a separate topic but is related to the discussion here.
The OE F41 rear bar is 22mm. The Hotchkis bar is 1" (making it maybe 70% stiffer than the OE bar, though still far below the stiffness of a dragstrip "antiroll bar").
On (earlier) edit because I came across it from an entirely different direction - check out the "SPOHN/SC&C ProTouring Swaybar" toward the bottom of the page at http://www.scandc.com/spohnarms.htm
Norm